Thermal responsive manually-operable switch



June 2 1925. I 1,540,692

- c. l. 'HALL THERMAL RESPONSIVE MANUALLY OPERABLE SWITCH Filed July 11 1921 Fig. I.

I O 5M! Inventor: Ch star 1-H a] I 103 Y I lfiw Hi0 Attorheg Patented June 2-, 1925 UNITED s TATES.

PATENT FFlCE.-'

CHESTER I. HALL,

or roar WAYNE, INDIANA, ASSIGNO-R 'ro GENERAL ELEc'rnIc.

COMPANY, A. CORPORATION OF NEW YORK. I

. rrmnmar. nEsPoNsIvE MANUALLY-OPEB ABLE swr'ron.

Application filed m 11,

To all 'w h am it may concern."

Be it known that I, CHESTER I..HAL L, a citizen of the United States,v residing at Fort Wayne, in the county of Allen, State of Indiana, have invented certainnew and useful Improvements in Thermal Responsive,

Manually-Operable Switches, of which the following is a specification.

My invention relates to improvements in electric switches and in particular to elec-.

, tric switches which are automatically operated responsively to the heating effect of an electric current. v

One of the objects of theinventionis to provide a switch which may be manually;

closed, and either manually opened with a snap action, or automatically opened with a snap action in response to the heating effect of a predetermined current for a prewhen thrown to one position and. for open ing the switch when thrown to its other position.

The invention relates to various advantageous features of construction and arrangement which will be pointed out particularly hereinafter, and the scope of the invention will be indicated in the appended claims.

For a better understanding of the inven-- tion, reference is had to the accomp'an ingdrawing which shows an embodiment 0 the invention for purposes of illustration, and m which Fig. 1 is a plan -view of an electric switch -withthe cover removed to show the switch operating mechanism; Fig. 2 is a cross-sectional view of the switch; and Fig. 2 3 is a detail for the purpose of showing the principle of operation of the switch..

For the purpose of quickly obtaining an 1 understanding of the invention, reference is first had to Fig. 3 in which the -pivotally mounted circuit controlling switch element 10 is .biased to the position shown in the drawings by means of the spring 11. The switch element is adapted tobe depressed into circuit closing position by means ofthe pi'votally mounted button 12 which is adapted to make enga ement with the right hand end of the swltc element 10. This operating button 12 carries a pivotally mounted 1921. Serial mf 483,729.

operating rod 13 which is provided for effecting the manual opening of the switch when desired. The swltch element is maintained in the circuit closed position by means of the thermostatic element 14 which serves as a latch andis adapted to make abutting and sliding engagement with the arm 15 of the switch element. The thermostatic-element is adapted to be heated in accordance with the current through theswitch b means of the heating coil 16 which is woun on and insulated from the element.

'The arrangement is such that when the switch is closed by the operation of the operating button, the end of the switch element 10 is brought into engagement with the v resiliently: mounted friction Iiiember 17 and the switc will be maintained closed by thethermostatic latch 14; until ,a current of a' predetermined value has persisted for a pre 'determlned time interval, whereu on' the latch 14 will fle'xrto the position s own in Fig. 3, and thus slide free of the arm 15 and thereby permit the switch element to return quickly with'a snap action to the open posi- .tion in accordance with the bias of thespring 11. I v The various parts of the switch are'mounted upon a supporting casing 18, which is provided with a cover 19 through which the manually o erative, pivoted, operating button 12 is a apted to pass so that the switch may be operated from the outside of the casmgby turnin thebutton 12 back and forth about its pivotal support. The thermostatic latch 14 is adjustable with respect to the arm 15 connected to the switch element by means of the adjusting screw; 20, and the arrangement is such that by raising the thermostatic latch the time 'takenby the latch. in releasing the switch member to return to thei'open position fora given value of current will be increased. This adjustment I may be effected either when the switch is open or when theswitch is closed. Turning theadjustmentscrew 20 in the opposite direction will shorten the time interval for opening. By reference: to Fig.1 it will. be seen that the switch element 10 is. adapted to make electrical contact between the stationary contacts 21 and 22 whenthe switch is closed, and it will also be seen that when the switch is closed the heating coil 16 is included in the circuit completed through the terminals 21 and 22.

It will be observed that I have provided a very neat and convenient arrangement for protecting electric circuits in accordance with the heating effect of the current in the circuit. It will also be seen that the switch is adapted to be manually closed by pressing the tumbler or pivoted operating button 12 to the right, and that the switch can either be manually operated to return to the open position with a snap action-by tilting the tumbler 12 to the left, thereby bringing the operating rod 13 into engagement with the thermal element 14 and flexing the latter to release the switch element 10, or the switch may be automatically opened responsively to the heating effect of the current in the controlled circuit by the flexing of the thermostatic latch 14 resulting from the heating thereof by the heating coil 16. Because of the fact that the free end of the thermostatlc latch makes a sliding and abutting engagement with the switch member, the friction is very small and the switch may be very easily adjusted to open at various time intervals for a given value of current. Although the switch has a comparatively few simple parts which can readily be enclosed within the casing of the ordinary tumbler switch, the switch is nevertheless reliable and effective in operation.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent thebest embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. A thermal responsive manually opcr able'switch comprising-a pivotally mounted circuit controlling switch element, means for biasing the same to the open position, an electrically heated thermostatic latch for holding the said switch element in circuit closed position against its bias to'the'open position, the said latch mounted-with one end thereof in position to make abutting and sliding engagement with the said switch element and the said end of the latch freely movable to slide out of engagement-with the said switch element'to release the same in accordance with the flexing of the latch due to the heating thereof, and manually operable means l'or mechanically moving the switch element to the closed circuit position and for flexing the said latch to release the switch element to return to the open circuit position independently of the heating of said thermostatic latch;

sition against its bias to the open position, a

an electric heating coil for heating the latch responsively to the current through the switch to cause the latch to flex and thereby release the switch element, and a pivoted manually operable member .for moving the switch element to the closed circuit position and for flexing the latch to release the said element to return to its normal open position. 4

3. A thermal responsive manually operable switch comprising a pivoted circuit controlling switch element, means for biasing the same to the open position, an electrically heated thermostatic latch for holding the said switch element in circuit closed position against its bias to the open position, the said latch mounted with a free end thereof in sliding abutting engagement with the said switch element and arranged to slide out of holding relation with the switch element when the latch is flexed due to the heating thereof, means for varying the relative positions of the said latch and switch element for adjusting" the time interval of the automatic openingof the switch for a given value of current, and a pivotally mounted manually operable member for moving the switch element to the closed position and for flexing the said latch to release the said element to return to the open position.

4. A thermal responsive tumbler switch comprising a casing, a pivoted circuit controlling switch element and a cooperating stationary switch element mounted within said casing, the said pivoted switch element being biased to the open-position, an electrically heated bi metallic thermostatic latch having one end secured to said casing and the free end thereof disposed in sliding latching relation with said switch element for holding the same in the closed position against its biasto the open position and arranged to slide outof latching relation with said switch element when the said latch is flexed due to the heating thereof, and a pivotally mounted manually operable tumbler extending through said casing and arranged to move the said switch element to the closed position when operated in one direction and to mechanically flex the said latch to release the said switch element to return to the open position when operated in the other direction.

-In witness whereof, I have hereunto set my hand this 1 day of July, 1921.

CHESTER I. HALL. 

